Projection type keyboard device

ABSTRACT

In a projection type keyboard device of the type wherein desired information is selected by means of a light pen on a keyboard upon which the information of the desired letter, digit, symbol and the like are selectively projected, the light for projecting the desired information and the light of the light pen are prevented from occuring simultaneously.

United States Patent 1191 1111 3,735,35

lwabuchi et al. 1 May 22, 1973 s41 PROJECTION TYPE KEYBOARD 2,924,321 2/1960 Ziskind et a1 ..250/220 M x EVIC 3,292,489 12/1966 Johnson et a]. ..340/324 R X r 32.2.". ,v 3,360,657 12/1967 [75] Inventors: Yasuo lwabuchi; Tomonori Yoshio- 3,443,332 5/1969 ka, both of Tokyo, Japan 1 3,495,232 2/1970 3,613,066 10/1971 Cooreman .178/l8 X [73] Assignee: Iwatsu Electric Company, Limited,

Tokyo, Japan Primary Examiner-David L. Trafton [22] Filed Jan 4 1971 Attorney--Chittick, Pfund, Birch, Samuels & Gauthier 21 Appl. No.2 103,680

57 ABSTRACT 52 us. (31......340/365 P, 250/219 FR, 250/220 M,

340/166 EL, 340/324 M, 340/337, 340/378 a P type devce the type B wherein desired mformatlon 1s selected by means of a light pen on a keyboard upon which the information g? of the desired letter, digit, symbol and the like are selectively projected, the light for projecting the 250/219 220 208; 340/324 desired information and the light of the light pen are 166 365 378 B; 178/18 prevented from occuring simultaneously.

[56] References Cited 4 Claims, 4 Drawing Figures UNITED STATES PATENTS 3,534,359 10/1970 Harris ..340/324 R PATENTEW 3.735.395

SHEET 1 UF 2 H BINARY BOIINIEH [IF Y may bo umn 3 L L f s 1 2 um REGISTER INVENTORS YASUO I WABUCH I TOMONORI YOS H IOKA ATTORNEY S PROJECTION TYPE KEYBOARD DEVICE BACKGROUND OF THE INVENTION This invention relates to a keyboard device capable of correctly selecting letters, digits or symbols which are to be projected on a screen by means of a light pen.

' The number of letters, digits, numerals, and symbols selected by such a keyboard amounts to from about 50 to 200 whereas, there are 1,000 to 2,000 in a Japanese typewriter. In either case a shift key is used or a plurality of instructions are provided for the key. In the case of a chinese character typewriter it is necessary to depress a combination of keys. This requires a troublesome operation and often causes miss-operation of the shift key.

SUMMARY OF THE INVENTION It is an object of this invention to provide an improved projection type keyboard device which can prevent objectional interference between the light for projecting the image and the light of the light pen.

In accordance with the invention, in a projection type keyboard device of the type wherein desired information is selected by means of a light pen on a keyboard upon which the formation of the desired letter, digit, symbol and the like are selectively projected, the light for projecting the desired information and the light of the light pen are prevented from occuring simultaneously.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawing FIG. 1 shows an exploded perspective view of various elements to explain the principle of this invention FIG. 2 shows a connection diagram of one example of the encoder utilized in this invention and FIGS. 3A and 3B show time charts helpful to explain the operation of the encoder shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT- With reference first to FIG. 1 of the accompanying drawing there is shown a keyboard I mounted on an operators table, not shown. Images of letters, digits, symbols, etc. recorded on a micro-film 2 are projected on a translucent screen, not shown, arranged in front of the keyboard by means of a light source 3 and a projection lens 4. When the selected letters and the like arenot projected on the screen, the micro-fihn 2 is advanced by a sprocket wheel 5 or an equivalent mechanism. To selectively display a desired letter on' the screen a light pen 6 is brought to the selected letter and then a switch is closed to pass current through a luminescent body 8 from an electric source 9 to cause it to luminesce. The light emanated in this manner is collected by a'condenser lens 10 and is then projected upon a photosensitive element 11 comprising a plurality of X signal conductors 12, a plurality of Y-signal conductors 13 which are arranged in a matrix and a plurality of photoelectric transducer elements 14 such as photodiodes disposed at respective crossings be tween conductors l2 and 13. Each photoelectric transducer element 14 corresponds to one of the letters to be projected on the screen. Accordingly, the light emitted from the light pen 6 impinges upon a photoelectric transducer element 14 corresponding to the position of the selected letter to activate the particular element. As

a consequence, when the activated photosensitive element is detected the desired keying operation will be made. However, when the projection of the selected letter and the detection thereof is made by light, the light used for the projection and the light emitted by the light pen interfere with each other thus disturbing accurate keying operations.

According to this invention, the source of projection light 3 is lighted at a definite interval under the control of a control source 15 and the light of the light pen 6 is projected upon the photosensitive element 11 during the quiescent periods of the source 3 thus assuring ready and accurate selection of the letters.

The encoder for the selected photoelectric transducer element 14 comprises X and Y-binary counters CX and CY, and matrix circuits MX and MY associated with binary counters CX and CY, respectively. The output terminals of matrix circuit MX are connected to X-signal conductors 12 of the photosensitive element 11 whereas output terminals of matrix circuit CY are connected to Y-signal conductors 13 of the photosensitive element 11' through gate circuits G through G connected to perform theoretical multiplying operations. In this example, the number of rows X and the number of columns Y are both four.

When a letter at an address (x y is selected, the light from the light pen 6 is projected on the portion of the screen corresponding to the position of the photosensitive element 11 bounded by a dotted line circle as shown in FIG. 2, so that a photoelectric transducer element at this portion becomes conductive. In the case when both X and Y represent a binary l a gate circuit G produces an output. This output ceases the generation of the clock pulse CP. The content 3 of X counter CX and the content 3 of Y-counter CY are utilized to encode the selected letter and the encoded letter is stored in a data register, not shown, through gate circuits G and G In FIG. 2 symbol S represents signals showing the number of pages of microfilm 2 and S, the closing signal for switch 7 of the light pen 6.

FIG. 3A shows the relationship among the operation (shown by S of the light source 3, the operation (shown by S of switch 7 of light pen 6 and the letter selecting operation (shown by CR) when light is emitted from the light pen in response to its switch. The reading of the position of the letter is performed at an instant shown by a pulse bounded by a dotted line circle. FIG. 3B shows the relation among operations of various elements shown in FIG. 2.

In the embodiment described above, although the projection of the image and the lighting of the light pen are alternately at a definite period it is to be noted that the circuit may be modified so that only when the switch of the light pen is depressed, the projectionof the image is ceased.

As above described in accordance with this invention the projection of the position of letters, symbols and the like on the keyboard for the purpose of informing the position to the operator and the lighting of the light pen are made alternately. When the light pen is lighted to select a photoelectric transducer element located at the desired position among a group of such elements, the light source for image projection is extinguished so that its light cannot interfere with light from the light pen and the S/N ratio is improved, thus assuring accu rate selection.

Accordingly, when used in combination with a pattern or letter display device utilizing a CRT the novel keyboard device is extremely advantageous for typesetting, editing and searching involving a number of letters.

While a particular embodiment of the invention has been shown and described, it will occur to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

1. In a projection type keyboard device of the type wherein desired information is selected by directing light from a light pen onto a keyboard upon which a plurality of characters are selectively projected by light from the back of said keyboard, the improvement which comprises means for preventing the light for projecting the desired characters and the light of the light pen from occurring simultaneously.

2. A method of operating a projection type keyboard device wherein a plurality of characters located in back of a screen are projected toward the screen by a light source and light from a light pen in front of the screen is selectively directed onto a selected projected character on the screen and onto a photosensitive element to input the selected character, said method further comprising the step of preventing light from said source from occurring simultaneously with light from said light pen.

3. The method as recited in claim 2 wherein light from said source occurs alternately with light from said light pen.

4. The method as recited in claim 2 wherein light from said source does not occur whenever said light pen is being operated.

(I ER'II I GATE 0 F C (l h R, EC? i ON Patent No. 5, 95 Dated May 22, 1973 Yasuo Iwabuchi and Tomonori Yoshioka lnvcntor(::) v

It is ccrti find that error appears in the abovc-idcntificd patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 9, "there are 1000" should read there are from 1000 Column 1, line 25, change "formation" to information Column 2, line 53, "are alternately" should be are performed alternately Column 3, after line 10, insert the following paragraph In the appended claims, the term "character" is used to denote letters, digits, symbols and the like.

Signed and sealed this 18th day of December 1973.

(SEAL) r Attest:

EDWARD M.FLET CHER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents 

1. In a projection type keyboard device of the type wherein desired information is selected by directing light from a light pen onto a keyboard upon which a plurality of characters are selectively projected by light from the back of said keyboard, the improvement which comprises means for preventing the light for projecting the desired characters and the light of the light pen from occurring simultaneously.
 2. A method of operating a projection type keyboard device wherein a plurality of characters located in back of a screen are projected toward the screen by a light source and light from a light pen in front of the screen is selectively directed onto a selected projected character on the screen and onto a photosensitive element to input the selected character, said method further comprising the step of preventing light from said source from occurring simultaneously with light from said light pen.
 3. The method as recited in claim 2 wherein light from said source occurs alternately with light from said light pen.
 4. The method as recited in claim 2 wherein light from said source does not occur whenever said light pen is being operated. 